Contemporary automotive cooling systems typically employ a plurality of coolant lines which circulate coolant through various portions of a vehicle. The coolant within these lines may be used to draw heat away from the engine, the transmission, or other portions of the vehicle (collectively referred to herein as the powertrain) where it is desirable to maintain a controlled temperature. In basic operation, the coolant draws heat away by heat transfer, wherein the heat of the powertrain is transferred to the coolant, thereby elevating the temperature of the coolant.
Once the coolant has drawn heat away from the powertrain, it is routed to a cooling package which may include a coiled or otherwise arrayed tubing configuration(s) commonly referred to as a radiator. Air is directed over the cooling package to reduce the temperature of the coolant so that it may be recirculated again to continue to draw heat away from the powertrain.
Reducing the temperature of the coolant is critical. If the coolant is not sufficiently cooled, it will not effectively absorb a sufficient amount of heat when recirculated. Such a condition can lead to overheating, seizing, etc. Typically, air is directed over the cooling package by two means, each of which operates to reduce the temperature of the coolant therein. First, when the vehicle is moving, ram air from outside the vehicle is directed over the cooling package. Second, when the vehicle is not moving, or when there is an insufficient amount of ram air to effectively reduce the temperature of the coolant, a fan is utilized to draw air over the cooling package. The fan may be engine driven via a belt or the like, or the fan may be electrically driven.
For certain types of vehicles, efficient fan operation is critical because the vehicle may experience high powertrain loads when stationary, i.e. when there is little to no ram air available. For example, firefighting apparatuses such as pumper trucks typically utilize the engine to drive the pump thereof for pumping a large quantity of water to fight a fire. As such, despite being stationary, the powertrain (particularly the engine) experiences a high load that causes the temperature thereof to elevate. The pumper truck must thus rely entirely on its internal fan for effective operation of its cooling system.
Unfortunately, many contemporary air cooling configurations are highly inefficient. More specifically, the fan in a contemporary cooling system, while typically placed in proximity to the cooling package, tends to draw air over only certain portions thereof and/or draw air over the cooling package unevenly. Such inefficient operation of the fan is due in part to the shape of the fan versus the shape of the cooling package. The cooling package is typically rectangular in shape, while the fan generates an air column that is generally cylindrical. As a result, portions of the cooling package may not be exposed to as much cooling air as other portions of the radiator.
Furthermore, air that is drawn over the cooling package increases in temperature as heat is transferred to the air from the coolant within the coolant package. This heated air has a tendency to remain in proximity to the cooling package, thus increasing the overall temperature of the cooling package and the air circulated therein. This condition can limit the ability of the air that is drawn over the cooling package to absorb a sufficient amount of heat from the cooling package. Indeed, because the engine and cooling package are situated within a generally enclosed engine tunnel, this heated air remains in proximity to the cooling package and increases the overall temperature of the environment within the engine tunnel, thus negatively effecting heat transfer efficiency.
Both of the above scenarios are undesirable as they can lead to insufficient cooling. Previous attempts to avoid the above have led to fan oversizing which gives rise to parasitic power loss of the powertrain given that a sufficiently large amount of energy generated by the power train is used to operate such oversized fans. Further, cost of procurement and operation are driven up given that the aforementioned oversized fans can be expensive. Therefore, there is a need in the art for a method and apparatus that will efficiently manage air flow used for powertrain cooling to avoid the above problems.
The invention provides such a system and method. These and other advantages of the invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.